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<a href="task__qing__thread_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="detail_2async__fwd_8hpp.html">flow/async/detail/async_fwd.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="preprocessor">#include &quot;<a class="code" href="async__fwd_8hpp.html">flow/async/async_fwd.hpp</a>&quot;</span></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="preprocessor">#include &quot;<a class="code" href="util__fwd_8hpp.html">flow/util/util_fwd.hpp</a>&quot;</span></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="preprocessor">#include &quot;<a class="code" href="log_8hpp.html">flow/log/log.hpp</a>&quot;</span></div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span><span class="preprocessor">#include &lt;boost/move/unique_ptr.hpp&gt;</span></div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="preprocessor">#include &lt;boost/thread/future.hpp&gt;</span></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span> </div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceflow_1_1async.html">flow::async</a></div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span>{</div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"></span> </div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment">/**</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="comment"> * Internally used building block of various concrete Concurrent_task_loop subclasses that encapsulates a thread</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment"> * that spawns at construction time and a dedicated-or-shared util::Task_engine (a/k/a boost.asio `io_context`)</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment"> * `run()`ning in that new thread.</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment"> *</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="comment"> * This class:</span></div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="comment"> *   - At construction:</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"> *     - Takes a ref-counted reference to an existing util::Task_engine, which may be fresh of</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment"> *       posted tasks or not; shared with another Task_qing_thread or not.</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> *     - Starts a thread, ultimately executing an indefinitely-running `Task_engine::run()`, thus</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> *       either comprising the single thread executing tasks from that `Task_engine`; or joining a pool</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> *       of such threads.</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span><span class="comment"> *       - `post(*(this-&gt;task_engine()), F)` can be used to queue up tasks to execute; and any already-queued</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span><span class="comment"> *         work on `*(this-&gt;task_engine())` may execute in this new thread as well.  (This is all thread-safe due to</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment"> *         the thread-safe nature of boost.asio util::Task_engine posting, including across thread creation and</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"> *         destruction.)</span></div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment"> *   - Ends* the thread and &quot;joins&quot; it in destructor.</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="comment"> *     - Can also do this earlier (but still irreversibly) via the stop() API.</span></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span><span class="comment"> *     - *If the `Task_engine` is shared with other `Task_qing_thread`s, per `own_task_engine` ctor arg,</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="comment"> *       then the `Task_engine::stop()` call must be executed by outside code instead.</span></div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment"> *   - Exits the program (!) if a task posted via task_engine() throws an uncaught exception.</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"> *   - Provides access to low-level underlying util::Thread via raw_worker_thread();</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment"> *     see async::optimize_pinning_in_thread_pool().  Note util::Thread in turn allows direct native access to</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment"> *     the OS thread object (pthread handle, or whatever).</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment"> *</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment"> * ### Design rationale ###</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment"> * Task_qing_thread() constructor doc header contains discussion worth reading.</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment"> */</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno"><a class="line" href="classflow_1_1async_1_1Task__qing__thread.html">   59</a></span><span class="keyword">class </span><a class="code hl_class" href="classflow_1_1async_1_1Task__qing__thread.html">Task_qing_thread</a> :</div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span>  <span class="keyword">public</span> <a class="code hl_class" href="classflow_1_1log_1_1Log__context.html">flow::log::Log_context</a>,</div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span>  <span class="keyword">private</span> boost::noncopyable</div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span>{</div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="keyword">public</span>:</div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span>  <span class="comment">// Constants.</span></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="comment"></span> </div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="comment">   * `exit()` code returned to OS in the event Task_qing_thread chooses to `exit()` the entire program (as of this</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment">   * writing, this occurs on uncaught exception by a user task).</span></div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment">   */</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno"><a class="line" href="classflow_1_1async_1_1Task__qing__thread.html#a981c21354bafc012748707a301b89d3e">   70</a></span>  <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">int</span> <a class="code hl_variable" href="classflow_1_1async_1_1Task__qing__thread.html#a981c21354bafc012748707a301b89d3e">S_BAD_EXIT</a>;</div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span> </div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span>  <span class="comment">// Constructors/destructor.</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment"></span> </div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment">   * Constructs object, immediately spawning new (worker) thread, memorizing a ref-counted reference to</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment">   * the provided util::Task_engine which may or may not be a fresh one and meant to be shared with other</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment">   * `Task_qing_thread`s or exclusively by this one.  The post-condition of this constructor is:</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment">   *   - If `done_promise_else_block` is null, it&#39;s:</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment">   *     - The new thread has started.</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment">   *     - If `init_func_or_empty` is not `.empty()`, then: `init_func_or_empty()` ran *first-thing* in that thread and</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment">   *       returned.</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment">   *       - Note: This is a useful guarantee, if, say, you need to perform some privileged actions at thread setup;</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment">   *         once this post-condition holds, it is safe to drop privileges.</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment">   *     - The thread is ready to participate in task-posting via `post(*this-&gt;task_engine(), F)` and</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment">   *       similar.</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment">   *   - If `done_promise_else_block` is *not* null, it&#39;s:</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment">   *     - None.  However, if one executes `done_promise_else_block-&gt;get_future().wait()`, upon return from that</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment">   *       statement, the above if-`done_promise_else_block`-is-null post-conditions will hold.</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment">   *</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment">   * @note `!done_promise_else_block` mode is typical.  Just wait for construction, then `post()` away.  The</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment">   *       other mode is helpful when one has an N-thread pool and wants each Task_qing_thread to initialize</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment">   *       concurrently with the others instead of serially.  Then one can pass in N `promise`s to N Task_qing_thread</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="comment">   *       ctor calls, then wait on the N respective `unique_future`s.</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="comment">   *</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment">   * @note When creating the util::Task_engine `task_engine`, it is usually a good idea for perf to pass the</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment">   *       concurrency-hint arg value 1 (one) if either `own_task_engine == true`, or the overall thread pool simply</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment">   *       will have but 1 thread.  This will allow boost.asio to optimize internal locking and such.</span></div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment">   *</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment">   * The worker thread started by each Task_qing_thread constructor will exit upon any uncaught exception by one</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment">   * of the user-supplied `Task`s `post()`ed onto it subsequently.  If this occurs, the handler will `exit()` the entire</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment">   * program with a non-zero code after logging (to `*logger_ptr`) the exception message.  (It is informally</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment">   * recommended that all other threads in the application do the same.)</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment">   *</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment">   * Assuming no such uncaught exception is thrown, the thread will run until stop() or the destructor is called and</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment">   * returns.</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment">   *</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment">   * ### Basic concept discussion: To share or not to share (a `Task_engine`)? ###</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment">   * The choice of `own_task_engine` flag, as of this writing, does not actually affect much of `*this` behavior.</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment">   * If `true`, then you&#39;re saying this is the only thread to run tasks on the `Task_engine` (call it E).</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment">   * If `false`, it may be shared with other threads.  In practice, though, as of this writing, this only controls</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment">   * whether stop() will perform `E-&gt;stop()` (which causes all `E-&gt;run()`s to return and hence threads to soon exit)</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment">   * for you (`true`), or you must do it for the shared E yourself (which has other objects like `*this` associated</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment">   * with it).  Either way, E can be used before or after `*this` thread runs in whatever way one prefers, including:</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment">   * one can pre-queueing tasks (via `post(*E, F)` and such) for it to join in executing in new thread; one can inherit</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment">   * any not-yet-executed tasks after stop(), to execute them in some other thread/run().</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment">   *</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment">   * That said, despite the small practical impact in *this* class, the decision of whether to assign one</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment">   * Task_qing_thread (and hence util::Thread and hence native thread) to a `Task_engine` in one-to-one fashion,</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment">   * versus sharing the latter with more `Task_qing_thread`s, is a central one to your design.</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment">   * It is central to specifying the pattern of how `post()`ed `Task`s are</span></div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment">   * spread across actual threads in a pool.  In particular, if it&#39;s `true` (not shared), then one *must*</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment">   * select a specific Task_qing_thread (and, therefore, its corresponding worker thread) before</span></div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment">   * actually `post()`ing; otherwise it will be selected intelligently by boost.asio.  On the other hand, if it&#39;s</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span><span class="comment">   * `false` (shared), then to guarantee two tasks FG will not execute</span></div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment">   * concurrently (&lt;= desirable if they&#39;re assigned to one async::Op) one must probably</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment">   * use a util::Strand.  Meanwhile if it IS `true` (not shared), then one can simply guarantee it by posting</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="comment">   * onto the same Task_qing_thread (i.e., worker thread)... which is straightforward but theoretically worse at</span></div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment">   * using available time slices across threads.  It&#39;s worse that way, but on the other hand thread-to-core-pinning</span></div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment">   * is arguably more predictable in terms of ultimate effect on performance when `Strand`s aren&#39;t used.  Plus it</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment">   * might cause thread-caching perf increases.</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment">   *</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment">   * Very informally, and perhaps arguably, the `true` (do-not-share-engine) mode is the legacy way and is how</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment">   * certain entrenched legacy daemons do it; the `false` (share-engine-among-threads) is the common-sense</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment">   * boost.asio-leveraging way which might be the default for new applications; but it depends also on perf analysis</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment">   * of thread caching benefits of the `true` way as well.</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment">   *</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span><span class="comment">   * ### Rationale/history ###</span></div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span><span class="comment">   * Also informally: The hairiness of forcing the user to have to make this decision, and then write potentially</span></div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span><span class="comment">   * `if`-laden code that subsequently actually posts tasks, is a chief motivation for abstracting such details</span></div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span><span class="comment">   * behind the interfaces Concurrent_task_loop and async::Op.  Then the user gets to just post `Task`s, optionally</span></div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span><span class="comment">   * tagged with `Op`s to prevent unwanted concurrency, while the aforementioned interfaces will deal with</span></div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment">   * the different ways of using Task_qing_thread.  Therefore, Task_qing_thread is a detail/ class not to be used</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span><span class="comment">   * by or exposed to the user.</span></div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="comment">   *</span></div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span><span class="comment">   * Historically, a certain proof of concept (PoC) started out by having &quot;user&quot; code deal with `Task_engine`s directly,</span></div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span><span class="comment">   * quickly morphing to wrap them with Task_qing_thread for ease of use.  Then once this PoC desired to have knobs</span></div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="comment">   * controlling how tasks are scheduled across threads, without having the &quot;user&quot; code worry about it after</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span><span class="comment">   * initial thread-pool setup, Task_qing_thread was moved from the public area into detail/, and Concurrent_task_loop</span></div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span><span class="comment">   * was born (along with with helper type async::Op).</span></div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span><span class="comment">   *</span></div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment">   * ### Logging subtlety ###</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span><span class="comment">   * For convenience, as promised by at least Cross_thread_task_loop::start() doc header: If user has specified</span></div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment">   * a Config::this_thread_verbosity_override() setting (to reduce or increase log volume temporarily), then</span></div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment">   * we take it upon ourselves to apply this setting to the spawned thread during exactly the following times:</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span><span class="comment">   *   - Any startup logging in the spawned thread, by `*this`.</span></div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment">   *   - Any shutdown logging in the spawned thread, by `*this`, after stop() triggers thread exit.</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment">   *</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="comment">   * @param logger_ptr</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment">   *        Logger to use for subsequently logging.</span></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment">   * @param nickname</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span><span class="comment">   *        Brief, human-readable nickname of the new thread pool, as of this writing for logging only.</span></div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span><span class="comment">   * @param task_engine</span></div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment">   *        The util::Task_engine E such that the body of the new thread will be essentially `E-&gt;run()`.</span></div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span><span class="comment">   * @param own_task_engine</span></div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span><span class="comment">   *        Essentially, `true` if you do not wish to share `*task_engine` with other `Task_qing_thread`s;</span></div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span><span class="comment">   *        `false` if you do wish to share it with other such threads.  See more detailed notes above.</span></div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="comment">   *        Also see stop().</span></div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment">   * @param init_func_or_empty</span></div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment">   *        If not `.empty()`, `init_func_or_empty()` shall execute first-thing in the new thread, before internal</span></div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment">   *        code begins the thread&#39;s participation in the `*task_engine` event loop (i.e., before task_engine-&gt;run()).</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span><span class="comment">   * @param done_promise_else_block</span></div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span><span class="comment">   *        If null, ctor will block until the thread has started and is ready to participate in</span></div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span><span class="comment">   *        `task_engine()-&gt;post()`ing (etc.; see above text).  If not null, then it will kick things off asynchronously</span></div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span><span class="comment">   *        and satisfy the `promise *done_promise_else_block` once the thread has started and is ready to p... you</span></div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span><span class="comment">   *        get the idea.</span></div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span><span class="comment">   */</span></div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span>  <span class="keyword">explicit</span> <a class="code hl_function" href="classflow_1_1async_1_1Task__qing__thread.html#abb03d1b5f50a2b6148da27139a2391da">Task_qing_thread</a>(<a class="code hl_class" href="classflow_1_1log_1_1Logger.html">flow::log::Logger</a>* logger_ptr, <a class="code hl_typedef" href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">util::String_view</a> nickname,</div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span>                            <span class="keyword">const</span> <a class="code hl_typedef" href="namespaceflow_1_1async.html#a968806f54b14c697fd76b3339a2bdbbf">Task_engine_ptr</a>&amp; <a class="code hl_function" href="classflow_1_1async_1_1Task__qing__thread.html#aaf0191625ae2613a7351dc0515398903">task_engine</a>, <span class="keywordtype">bool</span> own_task_engine,</div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span>                            boost::promise&lt;void&gt;* done_promise_else_block = 0,</div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span>                            <a class="code hl_class" href="classflow_1_1Function.html">Task</a>&amp;&amp; init_func_or_empty = <a class="code hl_typedef" href="namespaceflow_1_1async.html#af35fb65bdea1a3a92929ec2c4a6a6b72">Task</a>());</div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span><span class="comment"></span> </div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span><span class="comment">   * stop(), followed by forgetting the `Task_engine` returned by task_engine(); the latter action may</span></div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span><span class="comment">   * destroy that `Task_engine` synchronously.</span></div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span><span class="comment">   *</span></div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span><span class="comment">   * In particular task_engine() shall be destroyed by this destructor, unless you&#39;ve saved a copy of that `shared_ptr`</span></div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span><span class="comment">   * elsewhere (particularly in `own_task_engine == false` mode in ctor, it is likely to be saved in another</span></div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span><span class="comment">   * Task_qing_thread).</span></div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span><span class="comment">   *</span></div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span><span class="comment">   * Since stop() has the post-condition that the thread has been joined,</span></div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span><span class="comment">   * the same post-condition holds for this destructor.  It is, of course, safe to call this destructor after</span></div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span><span class="comment">   * already having called stop().</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span><span class="comment">   *</span></div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span><span class="comment">   * @see stop() which is useful when you want the thread to exit/be joined, but the underlying `Task_engine` must</span></div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span><span class="comment">   *      continue to exist for a bit; in particular `post()` on it would execute but do nothing.</span></div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span><span class="comment">   *      Then once you&#39;ve ensured no more such `post()`s are forthcoming, and hence it&#39;s safe,</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span><span class="comment">   *      &quot;finish the job&quot; by destroying `*this`.</span></div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno">  198</span><span class="comment">   *</span></div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span><span class="comment">   * @see task_engine() through which one can obtain a ref-counted util::Task_engine, for example with the idea</span></div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span><span class="comment">   *      to have another thread `task_engine()-&gt;run()`, thus inheriting any queued work/tasks and able to enqueue</span></div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno">  201</span><span class="comment">   *      and execute future ones.</span></div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno">  202</span><span class="comment">   */</span></div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span>  <a class="code hl_function" href="classflow_1_1async_1_1Task__qing__thread.html#abd3046b2dee9df486ba2710cb0d6b2e3">~Task_qing_thread</a>();</div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span> </div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span><span class="comment"></span> </div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno">  208</span><span class="comment">   * Returns pointer to util::Task_engine such that `post()`ing to it will cause the subsequent asynchronous execution</span></div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span><span class="comment">   * of that task in a way explained in the Task_qing_thread() constructor doc header.  This is the same object</span></div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span><span class="comment">   * passed to ctor.</span></div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span><span class="comment">   *</span></div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span><span class="comment">   * Do note that the user&#39;s saving a copy of this pointer can extend the life of the returned `Task_engine`</span></div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span><span class="comment">   * (which is NOT at all the same as extending the life of raw_worker_thread(); also NOT at all the same as</span></div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span><span class="comment">   * making it possible to actually execute work which requires threads).</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span><span class="comment">   *</span></div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno">  216</span><span class="comment">   * Could technically be `const`, but `const` usage is OK to be conservative.  In spirit, at least, it&#39;s not `const`.</span></div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span><span class="comment">   *</span></div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno">  218</span><span class="comment">   * @return See above.</span></div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno">  219</span><span class="comment">   */</span></div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span>  <a class="code hl_typedef" href="namespaceflow_1_1async.html#a968806f54b14c697fd76b3339a2bdbbf">Task_engine_ptr</a> <a class="code hl_function" href="classflow_1_1async_1_1Task__qing__thread.html#aaf0191625ae2613a7351dc0515398903">task_engine</a>();</div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span><span class="comment"></span> </div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno">  223</span><span class="comment">   * Returns the util::Thread -- a thin wrapper around the native OS thread handle -- corresponding to the worker</span></div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span><span class="comment">   * thread started in constructor.</span></div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span><span class="comment">   *</span></div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span><span class="comment">   * The intended use of this is to set thread attributes (such as processor-core</span></div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span><span class="comment">   * affinity) in a way that won&#39;t affect/disturb the concurrently executing thread&#39;s ability to execute tasks;</span></div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno">  228</span><span class="comment">   * meaning one might grab its native ID and then set some affinity attribute, but it wouldn&#39;t (say) suspend the</span></div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span><span class="comment">   * thread or join it.  Slightly informally, then: any such steps (&quot;such&quot; being the informal part) lead to undefined</span></div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span><span class="comment">   * behavior.</span></div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span><span class="comment">   *</span></div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span><span class="comment">   * @return Pointer to `Thread`, not null.  Guaranteed valid until destructor is invoked; guaranteed to be</span></div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno">  233</span><span class="comment">   *         not-a-thread after stop() and not not-a-thread before it.</span></div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><span class="comment">   */</span></div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span>  <a class="code hl_typedef" href="namespaceflow_1_1util.html#af030c3119f060a9630afca31098a78a5">util::Thread</a>* <a class="code hl_function" href="classflow_1_1async_1_1Task__qing__thread.html#a3f9a0071880455c00a993d36c6040ae5">raw_worker_thread</a>();</div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="comment"></span> </div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno">  238</span><span class="comment">   * Blocks the calling thread until the constructor-started thread has finished; if the underlying `Task_engine` is not</span></div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno">  239</span><span class="comment">   * shared then first signals it to stop executing any further `Task`s, thus causing the constructor-started thread</span></div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span><span class="comment">   * to in fact finish soon and hence this method to return soon.</span></div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span><span class="comment">   *</span></div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span><span class="comment">   * After stop() has returned once already, stop() will immediately return.  Concurrently executing stop() from</span></div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="comment">   * 2+ different threads leads to undefined behavior.</span></div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno">  244</span><span class="comment">   *</span></div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno">  245</span><span class="comment">   * In effect: If we own the `Task_engine` (`own_task_engine == true` in constructor), this method</span></div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span><span class="comment">   * causes the `Task_engine` to stop executing tasks ASAP and then waits as long as necessary for the thread to exit;</span></div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span><span class="comment">   * then returns.  This will be fast if `Task`s are well behaved (do not block).</span></div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span><span class="comment">   *</span></div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span><span class="comment">   * In effect: If we share an external `Task_engine` (`own_task_engine == false` in constructor), this</span></div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno">  250</span><span class="comment">   * method simply waits for the thread to exit as long as needed.  Hence the caller must trigger the shared</span></div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno">  251</span><span class="comment">   * `Task_engine` to exit this thread&#39;s `Task_engine::run()`.  (In particular, `Task_engine::stop()` will do this.)</span></div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span><span class="comment">   * Otherwise this method will block until then.</span></div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span><span class="comment">   *</span></div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span><span class="comment">   * The key fact is that, after this returns, the `Task_engine` returned by task_engine() shall not have been</span></div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span><span class="comment">   * destroyed by this method.  In particular, `post()` on that `Task_engine` object will still work without</span></div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span><span class="comment">   * undefined behavior/crashing.  The `post()`ed function just won&#39;t actually run.  (It may run on another thread but</span></div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno">  257</span><span class="comment">   * not this one, since by definition this thread has been joined.)</span></div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno">  258</span><span class="comment">   */</span></div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span>  <span class="keywordtype">void</span> <a class="code hl_function" href="classflow_1_1async_1_1Task__qing__thread.html#a6515b9f5240cea26b78e27ea99964ade">stop</a>();</div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno">  260</span> </div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span><span class="keyword">private</span>:</div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span>  <span class="comment">// Data.</span></div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span><span class="comment"></span> </div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span><span class="comment">  /// See task_engine().</span></div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno"><a class="line" href="classflow_1_1async_1_1Task__qing__thread.html#a1f4a96efdc1820ddbb4a4bf49c0d38e6">  265</a></span><span class="comment"></span>  <a class="code hl_typedef" href="namespaceflow_1_1async.html#a968806f54b14c697fd76b3339a2bdbbf">Task_engine_ptr</a> <a class="code hl_variable" href="classflow_1_1async_1_1Task__qing__thread.html#a1f4a96efdc1820ddbb4a4bf49c0d38e6">m_task_engine</a>;</div>
<div class="line"><a id="l00266" name="l00266"></a><span class="lineno">  266</span><span class="comment"></span> </div>
<div class="line"><a id="l00267" name="l00267"></a><span class="lineno">  267</span><span class="comment">  /// See constructor.</span></div>
<div class="line"><a id="l00268" name="l00268"></a><span class="lineno"><a class="line" href="classflow_1_1async_1_1Task__qing__thread.html#a0a80c87ce824a15fb84a73d99f5d61ac">  268</a></span><span class="comment"></span>  <span class="keywordtype">bool</span> <a class="code hl_variable" href="classflow_1_1async_1_1Task__qing__thread.html#a0a80c87ce824a15fb84a73d99f5d61ac">m_own_task_engine</a>;</div>
<div class="line"><a id="l00269" name="l00269"></a><span class="lineno">  269</span><span class="comment"></span> </div>
<div class="line"><a id="l00270" name="l00270"></a><span class="lineno">  270</span><span class="comment">  /// Thread created in constructor.  Not-a-thread after stop(); not not-a-thread before stop().</span></div>
<div class="line"><a id="l00271" name="l00271"></a><span class="lineno"><a class="line" href="classflow_1_1async_1_1Task__qing__thread.html#a75b218e1b5f137ead984588107ef02b0">  271</a></span><span class="comment"></span>  boost::movelib::unique_ptr&lt;util::Thread&gt; <a class="code hl_variable" href="classflow_1_1async_1_1Task__qing__thread.html#a75b218e1b5f137ead984588107ef02b0">m_worker_thread</a>;</div>
<div class="line"><a id="l00272" name="l00272"></a><span class="lineno">  272</span>}; <span class="comment">// class Task_qing_thread</span></div>
<div class="line"><a id="l00273" name="l00273"></a><span class="lineno">  273</span> </div>
<div class="line"><a id="l00274" name="l00274"></a><span class="lineno">  274</span>} <span class="comment">// namespace flow::async</span></div>
<div class="ttc" id="aasync__fwd_8hpp_html"><div class="ttname"><a href="async__fwd_8hpp.html">async_fwd.hpp</a></div></div>
<div class="ttc" id="aclassflow_1_1Function_html"><div class="ttname"><a href="classflow_1_1Function.html">flow::Function</a></div><div class="ttdef"><b>Definition:</b> <a href="common_8hpp_source.html#l00512">common.hpp:512</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html">flow::async::Task_qing_thread</a></div><div class="ttdoc">Internally used building block of various concrete Concurrent_task_loop subclasses that encapsulates ...</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8hpp_source.html#l00059">task_qing_thread.hpp:62</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html_a0a80c87ce824a15fb84a73d99f5d61ac"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html#a0a80c87ce824a15fb84a73d99f5d61ac">flow::async::Task_qing_thread::m_own_task_engine</a></div><div class="ttdeci">bool m_own_task_engine</div><div class="ttdoc">See constructor.</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8hpp_source.html#l00268">task_qing_thread.hpp:268</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html_a1f4a96efdc1820ddbb4a4bf49c0d38e6"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html#a1f4a96efdc1820ddbb4a4bf49c0d38e6">flow::async::Task_qing_thread::m_task_engine</a></div><div class="ttdeci">Task_engine_ptr m_task_engine</div><div class="ttdoc">See task_engine().</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8hpp_source.html#l00265">task_qing_thread.hpp:265</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html_a3f9a0071880455c00a993d36c6040ae5"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html#a3f9a0071880455c00a993d36c6040ae5">flow::async::Task_qing_thread::raw_worker_thread</a></div><div class="ttdeci">util::Thread * raw_worker_thread()</div><div class="ttdoc">Returns the util::Thread – a thin wrapper around the native OS thread handle – corresponding to the w...</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8cpp_source.html#l00309">task_qing_thread.cpp:309</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html_a6515b9f5240cea26b78e27ea99964ade"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html#a6515b9f5240cea26b78e27ea99964ade">flow::async::Task_qing_thread::stop</a></div><div class="ttdeci">void stop()</div><div class="ttdoc">Blocks the calling thread until the constructor-started thread has finished; if the underlying Task_e...</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8cpp_source.html#l00259">task_qing_thread.cpp:259</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html_a75b218e1b5f137ead984588107ef02b0"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html#a75b218e1b5f137ead984588107ef02b0">flow::async::Task_qing_thread::m_worker_thread</a></div><div class="ttdeci">boost::movelib::unique_ptr&lt; util::Thread &gt; m_worker_thread</div><div class="ttdoc">Thread created in constructor. Not-a-thread after stop(); not not-a-thread before stop().</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8hpp_source.html#l00271">task_qing_thread.hpp:271</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html_a981c21354bafc012748707a301b89d3e"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html#a981c21354bafc012748707a301b89d3e">flow::async::Task_qing_thread::S_BAD_EXIT</a></div><div class="ttdeci">static const int S_BAD_EXIT</div><div class="ttdoc">exit() code returned to OS in the event Task_qing_thread chooses to exit() the entire program (as of ...</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8hpp_source.html#l00070">task_qing_thread.hpp:70</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html_aaf0191625ae2613a7351dc0515398903"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html#aaf0191625ae2613a7351dc0515398903">flow::async::Task_qing_thread::task_engine</a></div><div class="ttdeci">Task_engine_ptr task_engine()</div><div class="ttdoc">Returns pointer to util::Task_engine such that post()ing to it will cause the subsequent asynchronous...</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8cpp_source.html#l00304">task_qing_thread.cpp:304</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html_abb03d1b5f50a2b6148da27139a2391da"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html#abb03d1b5f50a2b6148da27139a2391da">flow::async::Task_qing_thread::Task_qing_thread</a></div><div class="ttdeci">Task_qing_thread(flow::log::Logger *logger_ptr, util::String_view nickname, const Task_engine_ptr &amp;task_engine, bool own_task_engine, boost::promise&lt; void &gt; *done_promise_else_block=0, Task &amp;&amp;init_func_or_empty=Task())</div><div class="ttdoc">Constructs object, immediately spawning new (worker) thread, memorizing a ref-counted reference to th...</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8cpp_source.html#l00037">task_qing_thread.cpp:37</a></div></div>
<div class="ttc" id="aclassflow_1_1async_1_1Task__qing__thread_html_abd3046b2dee9df486ba2710cb0d6b2e3"><div class="ttname"><a href="classflow_1_1async_1_1Task__qing__thread.html#abd3046b2dee9df486ba2710cb0d6b2e3">flow::async::Task_qing_thread::~Task_qing_thread</a></div><div class="ttdeci">~Task_qing_thread()</div><div class="ttdoc">stop(), followed by forgetting the Task_engine returned by task_engine(); the latter action may destr...</div><div class="ttdef"><b>Definition:</b> <a href="task__qing__thread_8cpp_source.html#l00248">task_qing_thread.cpp:248</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Log__context_html"><div class="ttname"><a href="classflow_1_1log_1_1Log__context.html">flow::log::Log_context</a></div><div class="ttdoc">Convenience class that simply stores a Logger and/or Component passed into a constructor; and returns...</div><div class="ttdef"><b>Definition:</b> <a href="log_8hpp_source.html#l01609">log.hpp:1610</a></div></div>
<div class="ttc" id="aclassflow_1_1log_1_1Logger_html"><div class="ttname"><a href="classflow_1_1log_1_1Logger.html">flow::log::Logger</a></div><div class="ttdoc">Interface that the user should implement, passing the implementing Logger into logging classes (Flow'...</div><div class="ttdef"><b>Definition:</b> <a href="log_8hpp_source.html#l01280">log.hpp:1284</a></div></div>
<div class="ttc" id="adetail_2async__fwd_8hpp_html"><div class="ttname"><a href="detail_2async__fwd_8hpp.html">async_fwd.hpp</a></div></div>
<div class="ttc" id="alog_8hpp_html"><div class="ttname"><a href="log_8hpp.html">log.hpp</a></div></div>
<div class="ttc" id="anamespaceflow_1_1async_html"><div class="ttname"><a href="namespaceflow_1_1async.html">flow::async</a></div><div class="ttdoc">Flow module containing tools enabling multi-threaded event loops operating under the asynchronous-tas...</div><div class="ttdef"><b>Definition:</b> <a href="async__fwd_8hpp_source.html#l00074">async_fwd.hpp:75</a></div></div>
<div class="ttc" id="anamespaceflow_1_1async_html_a968806f54b14c697fd76b3339a2bdbbf"><div class="ttname"><a href="namespaceflow_1_1async.html#a968806f54b14c697fd76b3339a2bdbbf">flow::async::Task_engine_ptr</a></div><div class="ttdeci">boost::shared_ptr&lt; util::Task_engine &gt; Task_engine_ptr</div><div class="ttdoc">Short-hand for reference-counting pointer to a mutable util::Task_engine (a/k/a boost::asio::io_conte...</div><div class="ttdef"><b>Definition:</b> <a href="async__fwd_8hpp_source.html#l00198">async_fwd.hpp:198</a></div></div>
<div class="ttc" id="anamespaceflow_1_1async_html_af35fb65bdea1a3a92929ec2c4a6a6b72"><div class="ttname"><a href="namespaceflow_1_1async.html#af35fb65bdea1a3a92929ec2c4a6a6b72">flow::async::Task</a></div><div class="ttdeci">Function&lt; void()&gt; Task</div><div class="ttdoc">Short-hand for a task that can be posted for execution by a Concurrent_task_loop or flow::util::Task_...</div><div class="ttdef"><b>Definition:</b> <a href="async__fwd_8hpp_source.html#l00096">async_fwd.hpp:96</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html_ae4dc52186797094b3040379ff19124c9"><div class="ttname"><a href="namespaceflow_1_1util.html#ae4dc52186797094b3040379ff19124c9">flow::util::String_view</a></div><div class="ttdeci">Basic_string_view&lt; char &gt; String_view</div><div class="ttdoc">Commonly used char-based Basic_string_view. See its doc header.</div><div class="ttdef"><b>Definition:</b> <a href="string__view_8hpp_source.html#l00191">string_view.hpp:191</a></div></div>
<div class="ttc" id="anamespaceflow_1_1util_html_af030c3119f060a9630afca31098a78a5"><div class="ttname"><a href="namespaceflow_1_1util.html#af030c3119f060a9630afca31098a78a5">flow::util::Thread</a></div><div class="ttdeci">boost::thread Thread</div><div class="ttdoc">Short-hand for standard thread class.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00078">util_fwd.hpp:78</a></div></div>
<div class="ttc" id="autil__fwd_8hpp_html"><div class="ttname"><a href="util__fwd_8hpp.html">util_fwd.hpp</a></div></div>
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